The amount of space debris, of fairly substantial size, is constantly increasing. The increase in the amount of space debris is leading to an increase in the risk of collisions between satellites and/or with a space station. Some debris is considered to be critical because of its size and/or its position in zones referred to as at risk zones, for example a usable orbit. Mention may, for example, be made of scrapped satellites, rocket stages, which may be stationed in a usable orbit. Getting such debris out of orbit becomes an urgent matter in order to move them away from the usable orbit. The question then arises of how to remove this debris in order to reduce space pollution in a way that is effective and reliable. Indeed, reliable manoeuvres and equipment are needed in order to remove the debris otherwise undesired collisions and even more debris will result.
Various solutions have been suggested. Of these mention may be made of an articulated arm for seizing hold of the debris, a gigantic net or a robotic vehicle, all intended to capture the debris and return it to earth or to park it in an orbit referred to as a parking orbit, far removed from the usable orbits. These solutions are expensive and difficult to implement.
Another solution is to harpoon the target object in question, namely the debris, in order to tow it out of the at-risk zone. One major problem is with the stability of the harpoon. Indeed, the earth's atmosphere, that can be considered to behave like a viscous medium, generates air resistance. By contrast, in space, which is to say in a near-perfect vacuum, an object moving in that medium is almost completely free of air resistance. The result of this is that there is no aerodynamic effect on this object. In other words, in a vacuum, it is not possible to rely on the aerodynamic effects in order to keep the harpoon orientated along the axis of its path. Once launched, the harpoon, generally held by a cable, therefore no longer heads in the desired direction towards the target object. Additional constraints associated with the field of space have therefore to be taken into consideration when coming up with the solution for the device intended to harpoon the target object. In addition, the connection between the harpoon and the target object (i.e. the debris) can create disturbances in the path of the harpoon when the cable is unwound. And the cable can also become tangled when it is stored therein.